(a) Field of the Invention
The present invention relates to a communication method and apparatus, and more particularly, to a communication apparatus and method, which allow a mobile terminal to communicate with a server or gateway through a sensor network.
(b) Description of the Related Art
A sensor network consists of low power sensor nodes. A mobile terminal (mobile device) is used to receive various information stored in a server through the sensor network and displays it, or to allow a user to send specific information to the server.
Such a mobile terminal selects one of the sensor nodes of the sensor network as an agent to communicate with an upper server or gateway. That is, the mobile terminal transmits particular data to the upper server or gateway via the sensor node corresponding to the agent, and the gateway writes the sensor node corresponding to the agent of the mobile terminal and transmits all data transmitted from the upper server to the corresponding mobile terminal via the sensor node corresponding to the agent of the mobile terminal. The mobile terminal communicates with the upper server or gateway only via the selected agent until the next agent selection time. However, it is impossible to make sure whether the selected agent can provide an optimal path until the next agent selection time. Moreover, the selected agent may not be able to provide an optimum path for both of upstream data and downstream data. That is, even though the mobile terminal is moved and rendered incapable of communicating with the selected agent, it continues to attempt communication with the agent that has become uncommunicable until the next agent selection period. At this point, packets may be damaged.
In addition, the sensor nodes of the sensor network perform an operation for reducing energy consumption by using asynchronous low power MAC (Medium Access Control). Much energy may be consumed at the sensor nodes due to signaling for the selection of an agent between the mobile terminal and the sensor nodes, and this may cause a communication failure between the mobile terminal and the upper server.
The above information disclosed in this Background section is only for enhancement of understanding of the background of the invention and therefore it may contain information that does not form the prior art that is already known in this country to a person of ordinary skill in the art.